Post-acute rehabilitation for individuals with acquired brain damage (ABD) is considered a major public health concern. Millions of Americans live with residual symptoms of ABD severe enough to interfere with basic activities of daily living. Over the past three decades, considerable interest and controversy has arisen over the effectiveness and efficacy of cognitive rehabilitation. While there has been general support for the overall success of cognitive rehabilitation, a series of evidence-based reviews have cited the need for more systematic study of treatment outcomes to determine practice guidelines. A major target of cognitive rehabilitation is the remediation of problem-solving deficits, which pose a significant obstacle to the community integration of persons with ABD. Our prior funded research has demonstrated the efficacy of an innovative problem-solving group-treatment protocol for relatively higher functioning patients with ABD due to traumatic brain injury. In contrast to conventional neuropsychological approaches to assessment and rehabilitation, which focus on the steps of reasoning, our treatment methods are based on the premise that rehabilitation of problem-solving deficits must address two target areas: (a) problems in emotional self-regulation and (b) problems in logical thinking. In the proposed randomized clinical trial (n = 120), our goal is to extend our treatment methods to address the needs of outpatients with more severe cognitive deficits. Because such individuals need individualized training and one-to-one practice and repetition, the intervention will be delivered in an individual treatment modality. Our long-term objectives are to (a) contribute to the cumulative body of evidence regarding the effectiveness of cognitive rehabilitation and (b) disseminate an empirically validated treatment protocol with practical applications for enhancing the community integration of more impaired individuals with ABD due to a variety of etiologies. To address these objectives, we have the following specific aims for the proposed research: (a) to evaluate the efficacy of an individual problem-solving treatment geared toward persons with more severely compromised cognitive skills, (b) to demonstrate the applicability of our problem-solving treatment methods to individuals with ABD due to stroke, as well as those with ABD due to TBI, and (c) to clarify the relationship between baseline performance on timed attention tasks and treatment gains. The proposed research has direct relevance to public health by addressing the need for (a) systematic evidence for practice guidelines and (b) empirically validated treatment protocols for cognitive rehabilitation in individuals living with ABD.